2.5L M50TU

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   Hey guys!!
Is there anyone here with experience of aircond? My engine runs at 700 rpm but when I turn on the aircond the RPM drops to 500 RPM and the car make a vibration then afterwards it goes back to 700 RPM. 

What I have changed is a new idler valve, throttle body, ecu. I have checked the wiring from the aircond to the ecu. My car doesn't have a catalytic converter. Can this be the problem? My car does have an oxygen sensor. 

Thanks in advance 

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325ism50 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 15-October-2003 Location: Austria Status: Offline Points: 21	Topic: 2.5L M50TU Posted: 18-December-2003 at 15:44
	Hey guys!! Is there anyone here with experience of aircond? My engine runs at 700 rpm but when I turn on the aircond the RPM drops to 500 RPM and the car make a vibration then afterwards it goes back to 700 RPM. What I have changed is a new idler valve, throttle body, ecu. I have checked the wiring from the aircond to the ecu. My car doesn't have a catalytic converter. Can this be the problem? My car does have an oxygen sensor. Thanks in advance

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Webdunk Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Moderator Group M3 GT Register Joined: 16-October-2002 Location: Central Scotland Status: Offline Points: 5245	Posted: 18-December-2003 at 16:28
	Sounds pretty normal to me - the A/C loads the car's electrical system, causing a temporary drop in revs before it recovers. Suspect this may not actually be a problem


Magnum Man Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 20-October-2003 Location: United Kingdom Status: Offline Points: 10	Posted: 18-December-2003 at 17:04
	I would agree. The reduction in revs is caused by the air conditioning compressor being engaged as you swith on the ac on, with a resultant a load of several horse power being demanded of the engine...hence the dip & recovery you experience. One other key point is that the air con won't work if the outside temp is below 4 centigrade,this ensures that things don't freeze up. Your switches will glow as per usual when the buttons are pressed but the compressor will not engage. Hope this helps.

daddy cool Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member II Joined: 27-October-2003 Location: Sussex Status: Offline Points: 691	Posted: 18-December-2003 at 19:31
	it might be worth pointing out , if u dont allready know ! having air conditioning switched on can considerably reduce your fuel economy Only wanted to point it out incase u werent aware .
	e30 2.7 cab e30 325i e30 325 sport e30 318 touring e28 m5 e28 m535 e34 m5 e39 540 e36 318ti (green) e36 318ti (mauve)

325ism50 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 15-October-2003 Location: Austria Status: Offline Points: 21	Posted: 19-December-2003 at 14:04
	Hi guys - I am very happy now. My problem is sorted out. It was the wrong alternator. It should have been 140 amp not 80 amp (that's for 1.8 litre and mine is 2.5). Thanks to all who wrote in with advice